Scanned this from Guyot’s Elementary Geography, published by Scribner, Armstrong & Co in 1875. The map shown here might actually show 1868 borders as that apparently was the year the book was first copyrighted.
A map that was included in a 1991 book called Kipinga by Marc L Felix.
He probably used a contemporary map as backdrop to illustrate the
geographical distribution of different shapes of Kipinga or throwing
knifes throughout central Africa.